1. Field of the Invention
The present invention relates to an image processing apparatus that processes an image of a captured object, an image processing program recording medium, and an image processing method.
2. Description of the Related Art
In recent years, medical image processing apparatuses, as represented by capsule endoscopes, that sequentially capture time-series in-vivo images of a lumen while moving through the lumen have been developed. When a capsule endoscope is swallowed by a patient and thus introduced into the body, the capsule endoscope sequentially captures images and transmits the images to a receiving device outside the body while moving through the lumen due to peristalsis. The capsule endoscope is eventually excreted to the outside of the body. The in-vivo images of the subject that are captured by the capsule endoscope and then received by the external receiving device are sequentially displayed in chronological order on, for example, a diagnostic workstation and are checked by an observer, such as a doctor.
The capsule endoscope captures a large number of images. The diagnostic workstation performs a process for detecting, from the captured images, images from which possible abnormalities, such as bleeding, can be assumed as images to be observed, which reduces the burden of observing images on a doctor and the like. For example, a technique is well known in which an image is divided into blocks, tone information is calculated per block, the calculated tone information is clustered, and a block, which belongs to a cluster at a predetermined distance from a cluster of blocks constituting a normal mucosa, is extracted as an abnormal site (Japanese Laid-open Patent Publication No. 2005-192880). A technique is also well known in which an image with highlighted microcalcification shades is generated using a morphology filter that is a shape-dependent filter for detecting candidates of microcalcification shades (Japanese Laid-open Patent Publication No. 2002-99896).